Re: [PATCH 1/2] dt-bindings: media: qcom,sm8550-iris: Allow IOVA reservation memory-region

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The binding schema fails to enforce the second `memory-region` item (IOVA reservation) for the `qcom,x1e80100-iris` compatible, which strictly requires it to prevent system reboots.
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commit c0ad29924b6618f643fc065b86b7d5896e42b2ff
Author: Daniel J Blueman <daniel@quora.org>

dt-bindings: media: qcom,sm8550-iris: Allow IOVA reservation memory-region

In addition to the firmware-loaded codec carveout, some Iris platforms
need to declare an IOMMU IOVA reservation (a reserved-memory node with
iommu-addresses) to keep DMA away from IOVA ranges that earlier
firmware stages have already mapped through the SMMU.

> diff --git a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> index 9c4b760508b50..0d83bb86c6c3f 100644
> --- a/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> +++ b/Documentation/devicetree/bindings/media/qcom,sm8550-iris.yaml
> @@ -80,7 +80,11 @@ properties:
>    dma-coherent: true
>  
>    memory-region:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 2
> +    items:
> +      - description: Firmware-loaded codec carveout
> +      - description: IOMMU IOVA reservation region

[Severity: Medium]
Should the schema also enforce minItems: 2 for the qcom,x1e80100-iris
compatible in an allOf conditional block?

The commit message for the subsequent patch ("arm64: dts: qcom: hamoa: Reserve
low IOVA range for Iris") explicitly states that on X1-family hamoa platforms
(which use the qcom,x1e80100-iris compatible), missing the IOVA reservation
causes unhandled SMMU page faults and spontaneous device reboots.

Without an allOf constraint enforcing the second memory region item for this
compatible, incomplete device trees missing the mandatory reservation will pass
schema validation but cause runtime failures.

>  
>    operating-points-v2: true
>

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Sashiko AI review · https://sashiko.dev/#/patchset/20260601041336.9497-1-daniel@quora.org?part=1